Iconic lever-driven digital reverb & modulation effects unit.
The EMT® 250 Classic Electronic Reverb plug-in for UAD-2 and Apollo interfaces is a faithful emulation of the first digital reverb/modulation effects unit introduced in 1976.
Still regarded as one of the best-sounding reverb units ever made, the EMT 250 continues to leave an immeasurable mark on record-making history in the hands of studio legends like George Massenburg, Bruce Swedien, Daniel Lanois, Brian Eno, and Allen Sides.
- Track and mix with the only emulation of the EMT 250 reverb unit, fully endorsed by EMT International GmbH
- Dial in lush delay, phasing, chorus, and echo effects
- Add distinctive space and depth to drums, guitars, and vocals with the same algorithm found in the original hardware
- Harness plug-in-only features including Dry/Wet Mix, Wet Solo, and Hard bypass
Used on Countless Classics
The EMT 250's distinctive clear and open reverb sound has appeared on countless records, including Prince & The Revolution's Purple Rain, Elvis Costello's Spike, and modern classics like The Red Hot Chili Pepper's Stadium Arcadium.
Exclusively endorsed by EMT Studiotechnik
Fully endorsed by EMT, the UAD EMT 250 plug-in uses the same algorithm found in the original, extremely rare hardware — designed by Dr. Barry Blesser and EMT industrial engineer Peter Bermes* — modeling a sourced "golden unit" from Allen Sides' collection that resides at the famed Ocean Way Recording.
Added Versatility with New Features
The EMT 250 plug-in goes beyond the original hardware, adding modern, workflow enhancing features like Dry/Wet Mix, Wet Solo, and Hard bypass. With these useful additions, the EMT 250 plug-in is even more powerful than the iconic hardware.
EMT 250 Electronic Reverberator
Functional Overview
Program Modes
The EMT 250 offers six effect types: Reverb, Delay, Phase, Chorus, Echo, and Space. These effects are called "program modes" in the EMT 250. Only one mode can be active at a time.
Each program mode has up to five parameters that can be modified by the four main control "levers" plus the front/rear switch. The function of these controls varies per program mode (see below). Additionally, there are several global controls that have the same function in all modes.
Variable Control Functions
The function of control levers 1, 2, 3, and the Front/Rear switch depends upon which program mode is active. This is a primary consideration to remember when operating the EMT 250. The Program Mode Control Functions Table the varying functions of the control levers and the front/rear switch in each mode.
Important: The function of the "levers" and the front/rear switch changes depending on the program mode.
Each unique parameter in the plug-in retains a distinct value, but only the parameters that are active in the current program mode are visible in the graphical user interface. All parameters are always visible in Controls View (see "Controls View" in the UAD System Manual), even when they are not active in the current program mode.
Important: The value of lever parameters that are not active in the current program mode are not saved in sessions or presets. The unsaved parameters are marked with an asterisk in the Program Mode Control Functions Table.
When switching between program modes that have different parameters mapped to the same control, parameter values are retained within each mode (controls jump back to the prior value that was set in each respective mode).
Lever 4 Predelay
In all program modes, lever 4 controls the predelay (the initial delay before other processing occurs) of both channels (left and right). Predelay times of 0ms, 20ms, 40ms, and 60ms are available in 4 steps. The green LEDs on the right side of lever 4 display the current predelay value.
Mono/Stereo Operation
The EMT 250 hardware unit has one (mono) input. For accurate emulation when the plug-in is used in a stereo-in/stereo-out configuration, stereo signals at the plug-in input are summed to mono before processing; the dry signal is passed in stereo.
Four channels of processed audio, selectable with the Front/Rear Outputs switch, are generated from this mono input in all modes (with the exception of Echo, which has mono output only).
Front/Rear Outputs
The EMT 250 hardware unit has four discrete outputs. Two outputs were designed to be used as the main stereo left/right outputs, or the "front" left/right outs in quadraphonic applications. The other two outputs were used for the "rear" left/right signals in quad (or other creative applications). The UAD EMT 250 fully models the individual sonics of all four outputs.
The name of the "Front/Rear Outputs" switch is derived from the original hardware design. This control (which is unique to the plug-in) enables access to the processed quadraphonic signal in pairs, at either the front L/R or rear L/R outputs. When a different sound is available at the front and rear outputs, the yellow "LED ring" around the control is illuminated. For program modes that do not offer quadraphonic processing (e.g., Delay), the switch is re-purposed to sum the processed outputs to mono. In Echo mode, it functions as an input mute.
In some program modes, the yellow "LED ring" around the control is illuminated to indicate that changing the switch position will change the sound. For program modes that do not offer quadraphonic processing (e.g., Delay), the switch is re-purposed to sum the processed outputs to mono. In Echo mode, it functions as an input mute.
Automation
Some EMT 250 control functions change depending on the active mode (see Variable Control Functions). To accommodate this design, all EMT 250 parameters are exposed for automation and external control surfaces even if the parameter is not active in the current program mode.
Important: Parameters that are automated and/or externally controlled will have no effect if those parameters are not active in the current program mode.
Modeled I/O
All input and output characteristics of the EMT 250 are fully emulated in the plug-in. This includes all of its idiosyncrasies, such as the A/D and D/A anti-aliasing filters (which are not linear-phase), system latency, input clipping, and limited frequency response. All these quirks embellish the unique sonic signature.
EMT 250 Latency
The EMT 250's anti-aliasing filters for its A/D and D/A conversion are not linear-phase filters; therefore the emulation does not have a latency that is the same at all frequencies. Thus, we cannot report to the delay compensation engines a delay that is correct for all frequencies. The value we report is good at low frequencies, but becomes off at high frequencies.
Program Mode Controls
The details of each unique program mode are below, followed by descriptions of the global controls, which affect all program modes.
Control Functions
The table below displays the parameter that each control is mapped to for each of the EMT 250 program modes. See Variable Control Functions for details.
Program Mode Control Functions Table
|
Program Mode |
Lever 1 |
Lever 2 |
Lever 3 |
Lever 4 |
Front/Rear |
|---|---|---|---|---|---|
|
Reverb |
Reverb Decay |
LF Decay |
HF Decay (damping) |
Predelay |
Output Pair |
|
Delay |
Coarse Delay Time |
Fine Delay Time |
Selects L/R channel for time adjustment* |
Predelay |
Stereo/Mono |
|
Phase |
Phase (curve) |
(none)* |
(none)* |
Predelay |
Output Pair |
|
Chorus |
(none)* |
(none)* |
Variation |
Predelay |
Stereo/Mono |
|
Echo |
Coarse Delay Time |
Fine Delay Time |
HF Decay (damping) |
Predelay |
Input Mute |
|
Space |
(none)* |
(none)* |
(none)* |
Predelay |
Output Pair |
|
*The parameter values of lever positions marked with an asterisk are not saved in sessions or presets. |
|||||
Program Mode
The Program Mode buttons define which of the available program modes is active. The six program modes are: Reverb (REV), Delay (DEL), Phase (PHAS), Chorus (CHOR), Echo, and Space (SPC).
Click a Mode button to activate that program mode; the button is illuminated for the currently active mode (only one mode can be active at a time). Each program mode and its associated parameters are described in detail below.
Tip: See the Program Mode Control Functions Table for a matrix of controls that are available in each program mode.
Reverb
Reverb program mode offers the same all-time classic reverb algorithm that made the EMT 250 famous.
Decay Time (Lever 1)
Lever 1 controls the main reverb tail decay time. The red LEDs on the left side of lever 1 indicate the current decay time; the green LEDs on the right side of lever 1 are inactive.
The decay time range (at 1 kHz) is 0.4 seconds to 4.5 seconds, selectable via 16 steps.
LF Decay (Lever 2)
Lever 2 controls the low frequency decay time (at 300 Hz). The red LEDs on the left side of lever 2 display the current value; the green LEDs on the right side of lever 2 are inactive.
Four multipliers are available: x 0.5, x 1.0, x 1.5, and x 2.0. The multiplier refers to a factor of the main decay time (lever 1). Higher values (upper lever positions) generally result in more low frequency content in the reverb tail.
HF Decay (Lever 3)
Lever 3 controls the high frequency decay time. The red LEDs on the left side of lever 3 display the current value; the green LEDs on the right side of lever 3 are inactive.
Four multipliers (at 6 kHz) are available: x 0.25, x 0.33, x 0.5, and max. At the max position, the HF decay factor is x 1.0 at approximately three seconds. The multiplier refers to a factor of the main decay time (lever 1). Higher values (upper lever positions) generally result in more high frequency content in the reverb tail.
Predelay (Lever 4)
Lever 4 is used as a typical reverb predelay parameter. See Lever 4 Predelay for more information.
Front/Rear
In Reverb mode, the Front/Rear Outputs switch is illuminated. Changing the switch setting will yield a slightly different effect. See Front/Rear Outputs.
Delay
Delay program mode offers two independent delay processors, one each for the left and right output channels. Up to 375 ms delay time is available for each channel. Delay repeats (feedback) are not available in Delay mode; use Echo mode if delay feedback is desired.
Note: The maximum per-channel delay time of 375 ms in Delay mode is obtained by setting the coarse, fine, and predelay times to their respective maximum values.
Coarse Delay Time (Lever 1)
Lever 1 controls the coarse delay time for the currently selected channel (left or right). The currently selected channel is defined by lever 3.
The coarse delay time range is 0 to 300 ms, selectable via 16 steps. The green LEDs on the right side of lever 1 display the current value; the red LEDs on the left side of lever 1 are inactive.
Fine Delay Time (Lever 2)
Lever 2 controls the fine delay time for the currently selected channel (left or right). The currently selected channel is defined by lever 3.
Fine delay times of 0ms, 5ms, 10ms, and 15ms are available. The green LEDs on the right side of lever 2 display the current value; the red LEDs on the left side of lever 2 are inactive.
Note: Levers 1 and 2 both control the delay time, but these parameters are not individually exposed for external control surfaces and automation. Instead, a single delay time parameter is exposed for each channel, and levers 1 and 2 in the plug-in interface are both updated to match the value.
Channel Select (Lever 3)
Important: In Delay mode, lever 3 selects which channel (left or right) the delay time parameters (levers 1 and 2) will affect. When lever 3 is in position "L" the left channel delay time can be adjusted; when in position "R" the right channel delay time can be adjusted.
The green LEDs on the right side of lever 3 display the channel selected for delay time adjustment; the red LEDs on the left side of lever 3 are inactive.
Note: Lever 3 position "I" is a duplicate of position "II - L" in Delay mode. Likewise, position "IV" is a duplicate of position "III - R." All positions can be used to select a channel for delay time adjustment.
Important: In Delay mode, lever 3 does not control a "real" parameter; it is only used to select the active channel for other parameters in the graphical user interface. For this reason, the parameter is not exposed for external control surfaces or automation, nor is it saved in sessions or presets.
Predelay (Lever 4)
Lever 4 can be used as a common predelay to both channels (the predelay time is added to the delay times of both channels). See Front/Rear Outputs for more information.
Front/Rear
In Delay mode, the Front/Rear Outputs switch is not illuminated (the sound is identical in both pairs of outputs). When moved to the Rear position, the plug-in output is summed to mono. See Front/Rear Outputs for more information.
Phase
Phase program mode creates a comb filter curve that results from the addition and subtraction of two signals with a small time shift between them. The comb filter changes the amplitude of the source signal's harmonic overtones, resulting in interesting tonal variations.
Tip: Phasing is most apparent when the plug-in is set to 100% wet (or when Wet Solo is active).
In the EMT 250, the input is fed to two delay processors; one with a fixed delay time of 15 ms, and the other which is variable from 0-15 ms, controlled by lever 1. By changing this variable "time shift" the phase (shape) of the comb filter, and therefore the timbre of the output signal, is changed.
Note: Unlike many "phasors," the EMT 250 does not modulate the variable "time shift" with a low frequency oscillator (LFO), which results in the continuously varying "swooshing" effect that is often associated with the process name. This conventional phasor effect can be reproduced (with outstanding results) by moving lever 1 back and forth, either manually or with automation.
Phase (Lever 1)
In Phase program mode, lever 1 controls the delay time (the phase time shift) between the two signals that create the comb filter. Phase values of 0 ms to 15 ms are available, selectable via 16 steps.
In Phase mode the green LEDs to the of right lever 1 are active, but the panel markings (0 - 300 ms) do not represent the actual phase delay time values. Instead, the LEDs indicate the relative value between 0-15 ms.
Predelay (Lever 4)
Lever 4 can be used as a common predelay to both phase delays. See Lever 4 Predelay for more information.
Note: Levers 2 and 3 have no effect in Phase program mode.
Front/Rear
The Front/Rear Outputs switch is illuminated in Phase program mode. Changing the switch setting will yield a different comb filter phase. Due to the nature of the effect in Phase mode, when the switch is in the Rear position and the Phase time (lever 1) is at minimum and maximum values, the signal is only output on one side (right-only at minimum, left-only at maximum). This behavior is identical to the original hardware. See Front/Rear Outputs for more information.
For more information about phasing, see the "Flangers and Phasers" article in the December 2008 Webzine:
Chorus
Chorus program mode creates an ensemble effect by simulating the impression of multiple imprecisions added to the original signal. In EMT 250, this is accomplished by routing the same signal to four delay processors, each having short delay times that are continuously and randomly modulated.
While it was necessary to combine the various physical outputs for variations of Chorus complexity, the EMT 250 plug-in is "pre-mixed" in four popular combinations.
Note: Levers 1 and 2 have no effect in Chorus program mode.
Chorus Mode (Lever 3)
Four subtle variations of the chorus effect are available (I, II, III, and IV). Lever 3 specifies the current variation.
Positions I and II are of a simpler nature, while III and IV are more complex. Position I duplicates the Left Front and Right Front outputs of the hardware. II duplicates Left Rear and Right Rear outputs of the hardware. III combines both the Left Front and Left Rear on the left side, and Right Front and Right Rear on the right. IV combines Left Front, Left Rear and Right Rear on the left side, and Left Rear, Right Front and a phase inverted Right Rear on the right. IV imparts a pseudo-quadraphonic sound.
Predelay (Lever 4)
Lever 4 is can be used as a common predelay to all four delays. See Lever 4 Predelay for more information.
Front/Rear
In Chorus mode, the Front/Rear Outputs switch is not illuminated (the sound is identical in both pairs of outputs). When moved to the Rear position, the plug-in output is summed to mono. See Front/Rear Outputs for more information.
Echo
Echo program mode produces a single monophonic delay effect, with feedback and adjustable delay time. Up to 375 ms of delay is available.
The feedback (recirculation) circuit is always active in Echo mode. The feedback signal path is attenuated by approximately 10% per loop circulation, and includes an adjustable high frequency attenuator for damping.
Note: The maximum delay time of 375 ms in Echo mode is obtained by setting the coarse, fine, and predelay times to their respective maximum values.
Coarse Echo Time (Lever 1)
Lever 1 controls the coarse delay time. The coarse delay time range is 0 to 300 ms, selectable via 16 steps.
The green LEDs on right side of lever 1 display the current value; the red LEDs on the left side of lever 1 are inactive.
Fine Echo Time (Lever 2)
Lever 2 controls the fine delay time. Fine delay times of 0 ms, 5 ms, 10 ms, and 15 ms are available. The green LEDs on right side of lever 2 display the current value; the red LEDs on the left side of lever 2 are inactive.
Note: Levers 1 and 2 both control the echo time, but these parameters are not individually exposed for external control surfaces and automation. Instead, a single echo time parameter is exposed, and levers 1 and 2 in the plug-in interface are both updated to match the value.
HF Decay (Lever 3)
Lever 3 controls the high frequency damping in Echo mode. The red LEDs on left side of lever 3 display the current value; the green LEDs on the right side of lever 3 are inactive.
Four multipliers are available: x 0.25, x 0.33, x 0.5, and max. Higher values (upper lever positions) result in more feedback.
Predelay (Lever 4)
Lever 4 is used as a predelay to the echo processor in this mode. The predelay time is added to the echo times, but not to the HF decay feedback loop. See Lever 4 Predelay for more information.
Front/Rear
The Front/Rear Outputs switch is not illuminated in Echo mode (the same monophonic signal is generated at the front and rear outputs). However, the Front/Rear Outputs switch has a special function in Echo mode.
In the Front position, the program behaves normally. In the Rear position, the input to the echo processor is muted, while still allowing the echo output to be passed. This feature is useful for adding echo to specific passages only, by flipping the switch to Front when echo is desired. The behavior is identical to the popular "dub" switch on the Roland RE-201. See Front/Rear Outputs for more information.
Space
Space mode is a special reverb program with an extremely long decay time and linear distribution of the reverberation time with frequency (all frequencies decay at the same rate). Because this condition doesn't exist in nature, and the program was originally intended for science fiction productions, the "reverberation in outer space" moniker was derived.
The reverb decay time is approximately 10 seconds in Space mode. Predelay and Front/Rear are the only adjustable parameters in this program mode.
Note: Levers 1, 2, and 3 have no effect in Space mode.
Predelay (Lever 4)
Lever 4 is used as a typical reverb predelay parameter. See Lever 4 Predelay for more information.
Front/Rear
In Space mode, the Front/Rear Outputs switch is illuminated. Changing the switch setting will yield a slightly different effect. See Front/Rear Outputs for more information.
Global Controls
The global controls are not program-specific; they apply to all program modes.
Power
The Power button (the red EMT logo) determines whether the plug-in is active. It is useful for comparing the processed signal to the original signal. Click the button to disable the plug-in; click it again to enable it.
When Power is in the Off (unlit) position, plug-in processing is disabled, and UAD DSP usage is reduced.
Note: UAD-2 DSP usage is reduced only when DSP LoadLock is disabled. If DSP LoadLock is enabled (the default setting), disabling Power will not reduce DSP usage.
Input Meter
The Input Meter indicates the level going into the plug-in. On the original hardware, the red "Register" LED illuminates when digital full code is reached, at 6 dB above 0 dB (i.e., there is 6 dB of headroom on the hardware, as the meaning of "0 dB digital" wasn't yet standardized in those days).
The distortion characteristics of the A/D converters are modeled, therefore "EMT 250-style" clipping can be heard when the EMT 250 input is overdriven.
Dry/Wet
The Dry/Wet slider control determines the balance between the original and the processed signal. The range is from 0% (dry, unprocessed) to 100% (wet, processed signal only).
This control uses a logarithmic scale to provide increased resolution when selecting lower values. When the slider is in the center position, the value is 15%.
Note: If Wet Solo is active, adjusting Dry/Wet will have no effect.
Wet Solo
The Wet Solo button puts the EMT 250 into "100% Wet" mode. When Wet Solo is on, it is the equivalent of setting the Dry/Wet control to 100% wet.
Wet Solo defaults to On, which is optimal when using the EMT 250 in the "classic" reverb configuration (placed on an effect group/bus that is configured for use with channel sends). When the EMT 250 is used on a channel insert, this control should be deactivated.
Note: Wet Solo is a global (per EMT 250 plug-in instance) control.
Noise
When Noise is active, the noise characteristics of the original hardware unit are fully intact. Disabling Noise eliminates the modeled noise characteristics for quieter operation.
Noise is active when the yellow LED is illuminated; it is enabled by default. Click the LED to change the setting.
The Noise parameter is unique to the UAD EMT 250 plug-in. Noise is dynamic to the response of the effect processing, and the noise level differs from program to program. The noise floor of the hardware EMT 250 may seem a bit high when compared to modern digital processors, but it adds to the EMT 250's quirky character.